The present invention relates to a display device, especially to a type of display device which is attached on a wall, such as an electric bulletin board, an advertisement sign board or the like.
Wall display devices, such as electric bulletin boards and advertisement sign boards, are widely used as means for providing information to many and unspecific people on streets. Such a wall display device usually includes a number of display elements arranged on a plane to form a two-dimensional matrix array of pixels in which an individual element is used for a pixel. The respective display elements are electrically actuated in various manner to display information. In an electric bulletin board, for example, one light bulb is used as one display element for one pixel, and a plurality of the light bulbs are arranged in matrix. By illuminating those of the light bulbs in specified positions, it is possible to display letters and pictures. Recently electric bulletin boards using light emitting diodes in place of light bulbs are widely used.
In an advertisement sign board, xe2x80x9cpanel display elementsxe2x80x9d are used as display elements to constitute respective pixels. The xe2x80x9cpanel display elementsxe2x80x9d are not light emitting themselves but have a plurality of display faces only one of which is actually displayed. Usually one of the display faces to be displayed can be selected by using a rotary mechanism, such as a motor or the like. One display face is selected for each pixel, whereby letters or pictures can be displayed.
Display elements for respective pixels, which are thus provided by light bulbs, light emitting diodes, panel display elements or the like, are electrically actuated. The light bulbs and the light emitting diodes, for example, can be switched between their light emitting state and non-light emitting state by On/Off control of electric power supply. By conducting the On/Off control on the respective light bulbs or the respective light emitting diodes which provide respective pixels, only required pixels can be selectively illuminated, whereby required information can be displayed. In the panel display elements the On/Off control of electric power supply to the motor is conducted, whereby those of the display faces to be actually displayed can be selected. The On/Off control is conducted on the respective panel display elements providing the respective pixels, whereby a required display face for each pixel can be displayed and required information can be displayed.
In the above-described display devices, needless to say, larger numbers of pixels are necessary for improvement of their display resolution. Accordingly it is necessary that a large number of display elements for respective pixels are arranged in a matrix. However, in order to increase a number of display elements, a number of wiring lines for the display elements must be increased. Therefore, a structure of a display device becomes complicated, which need much labor for its manufacture and maintenance. This results in higher manufacturing costs and maintenance costs.
In order to solve such problems, in the International Application No. PCT/JP95/00901 based on the Patent Cooperation Treaty, there is disclosed a novel technology in which a large number of display units having address recognition function are arranged in a matrix form to thereby constitute a display device. In this novel display device, since respective display units have address recognition function, it is possible to respectively independently control individual display units by a common signal through a common transmission passage. Accordingly, even if the number of display elements is increased, there is no possibility that wiring becomes complicated. Namely, if a particular display instruction is to be given to a specific display unit, it is sufficient to give such a display instruction along with address information indicating this specific display unit. When such an approach is employed, even if a common signal transmission passage is used as wiring for the respective display units, the individual display units can judge, by making reference to the address information, whether or not the given display instruction is directed to themselves.
In addition, in the International Application No. PCT/JP96/00058 based on the Patent Cooperation Treaty, there is disclosed a novel display device providing individual display units with memories in which respective display operations are stored in advance. In this display device, since the display units store respective own display operations for themselves in advance, it is possible to execute the display operations stored in advance even if no instruction is given from the external.
An object of this invention is to provide a novel technique for more efficiently operating a display device which provides a large number of display elements in a matrix form corresponding to respective pixels to constitute a two-dimensional pixel arrangement, wherein the respective display elements are driven by electric power to vary their display state.
(1) A first feature of the invention resides in a display device in which a plurality of display elements are arranged in a matrix form to constitute a two-dimensional pixel arrangement so as to display information on the two-dimensional pixel arrangement, each of the display elements having a function to change a display state of a pixel by applying electric power, the display device comprising:
a device body including plural display elements for constituting the two-dimensional pixel arrangement and a controller for changing display states of the plural display elements;
an electric power source for delivering electric power to the display elements; and
a control unit for delivering a display signal for designating display states of the display elements;
wherein plural kinds of divisional modes for dividing the two-dimensional pixel arrangement into plural blocks are defined, the respective divisional modes being represented by divisional level information indicating fineness of division, and address information for indicating the respective blocks are defined for the respective divisional modes;
wherein the control unit delivers, to the controller, a display signal including divisional level information, address information and data information; and
wherein, when the display signal is supplied to the controller, the controller executes a display operation for changing a display state of a display element or elements belonging to a particular block indicated by the address information so that the display state is changed to a new state indicated by the data information, the particular block being selected from among the plural blocks which are obtained when the two-dimensional pixel arrangement is divided by a divisional mode indicated by the divisional level information.
(2) A second feature of the invention resides in a display device having the first feature:
wherein a divisional mode indicated by a divisional level n is defined in which the two-dimensional pixel arrangement is divided by 2n in length and breadth directions so that 22n number of blocks are obtained and N kinds of divisional modes are defined with respect to n=1, 2, . . . , i, . . . N.
(3) A third feature of the invention resides in a display device having the second feature:
wherein, with respect to four blocks obtained in a divisional mode indicated by a divisional level n=1, they are respectively indicated by addresses consisting of 2 bits of 00, 01, 10, 11; and
wherein, with respect to 22i blocks obtained in a divisional mode indicated by a divisional level n=i, they are respectively indicated by addresses obtained by adding any one of 00, 01, 10, 11 to low order sides of addresses indicating 22(ixe2x88x921) blocks obtained in a divisional mode indicated by a divisional level n=(ixe2x88x921).
(4) A fourth feature of the invention resides in a display device having the third feature:
wherein divisional level information, address information and data information are respectively represented by bit or bits, a bit length of the divisional level information being fixed and a sum of a bit length of the address information and a bit length of the data information being fixed, and the bit length of the address information is recognized on the basis of the divisional level information.
(5) A fifth feature of the invention resides in a display device having any one of the first to the fourth features:
wherein when the two-dimensional pixel arrangement is divided based on a divisional mode finer than a display element so that portions of a display element respectively belong to plural different blocks, an operation to obtain uniformed combined data information is executed on the basis of respective data information corresponding to the plural different blocks and a display state of the display element is changed on the basis of the combined data information.
(6) A sixth feature of the invention resides in a display device having the fifth feature:
wherein in a time period during which an operation for obtaining uniformed combined data information is executed on the basis of a first display signal delivered for a purpose of changing a display state of a specific display element, when a second display signal for a purpose of changing a display state of the specific display element is delivered and the second display signal indicates a division coarser than that of the first display signal, the operation based on the first display signal is stopped and a new operation based on the second display signal is executed.
(7) A seventh feature of the invention resides in a display device having any one of the first to the sixth features:
wherein the control unit delivers a display signal including divisional level information, address information, data information and a time code; and
wherein the controller is operative so that when it is supplied with the display signal, it changes a display state at a timing synchronous with the time code.
(8) An eighth feature of the invention resides in a display device having the seventh feature:
wherein when the controller is supplied with plural display signals including a same time code and different divisional levels from each other, the controller selects a display signal having a divisional level in conformity with a number of display elements constituting the two-dimensional pixel arrangement among the plural display signals and executes only an operation based on the selected display signal.
(9) A ninth feature of the invention resides in a display device having any one of the first to the eighth features:
wherein the control unit generates plural display signals different in divisional levels on the basis of a same picture image and delivers the plural display signals in order from a display signal coarse in division to a display signal fine in division.
(10) A tenth feature of the invention resides in a display device having any one of the first to the eighth features:
wherein the control unit generates a display signal for a portion of a screen where a change takes place with respect to a series of picture images and delivers the display signal to the controller to provide a moving picture.
(11) An eleventh feature of the invention resides in a display device having any one of the first to the tenth features:
wherein plural display units are provided to constitute a device body, each of the display units including display elements, control elements for controlling an electric power supply to the display elements, memory means for storing predetermined address information, and a controller for controlling the control elements on the basis of address information stored in the memory means and a display signal delivered from a control unit; and
wherein different address information is stored in the respective memory means of the respective display units, and each of the controllers is operative so that when address information stored in the memory means and address information within the delivered display signal are in correspondence with each other it controls the control elements on the basis of data information within the delivered display signal.